Influences of deposition parameters on microstructure and dielectric properties of BST thin film deposited by R.F. magnetron sputtering

Abstract

Down graded barium strontium tianate(BST) thin films were prepared on Pt/Ti/SiO2/Si(100) substrate by radio frequency magnetron sputtering. The BST thin films were deposited at various substrate temperatures, then annealed at 700 °C for an hour. The influences of the deposition parameters on the crystallization behavior, microstructure and dielectric properties of BST thin films were investigated by X-ray diffraction, field emission scanning electron microscopy and dielectric frequency spectra. XRD results indicate that the BST thin films deposited at higher temperature have improved crystallization structure.The SEM observations show that the surface of the films is smooth with homogeneous grains.The dielectric properties of the films have been examined and discussed. The experiments show that BST thin films deposited at 650oc, 3.0Pa working pressure exhibits superior dielectric properties: the highest dielectric constant is 448 and lowest dielectric loss is 0.013 at 100 kHz, respectively. These results make BST thin films be a promising candidate for microelectronic device application.